← INDEX — FIG. 00 — GRB 221009A, 9 OCTOBER 2022
z = 0.151 · ≈ 1055 erg
BURST
GAMMA-RAY BURSTS: SWIFT & FERMI
A few times a day a flash of gamma rays outshines everything else.
BEGIN — CHAPTER 01 →CH.01 / 09 — VELA, 1967–1973
A flash that was not a bomb
Vela, 2 July 1967.
Sixteen bursts, 1973.
DIRECTION FROM ARRIVAL TIMES
cos θ = c · Δt / D
Timing triangulation.
CH.02 / 09 — BATSE, 1991–2000
An even sky, so a very long way off
BATSE: 2,704 bursts, isotropic.
Isotropy plus a faint-burst deficit.
INSTRUMENT 1 · DISK OR UNIVERSE?
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Illustration.
CH.03 / 09 — SHORT AND LONG
Two families, split at about two seconds
T90 and two classes.
Collapsars and mergers.
INSTRUMENT 2 · 4,391 REAL DURATIONS
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GBM catalog data.
CH.04 / 09 — SWIFT AND FERMI
A camera with no lens, and a sky watched at once
Coded mask.
Fermi and afterglows.
Mission tables.
CH.05 / 09 — DISTANCE AND ENERGY
The brightest burst ever recorded
E_iso and GRB 221009A.
Solar rest-mass comparison; GRB 090423.
ISOTROPIC-EQUIVALENT ENERGY
Eiso = 4π dL² S / (1 + z) · dL = (1 + z) (c/H₀) ∫₀z dz′ / √(Ωm(1 + z′)³ + ΩΛ)
Planck 2018 cosmology.
INSTRUMENT 3 · HOW FAR, HOW MUCH
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Presets and sources.
CH.06 / 09 — BEAMING
Only the ones pointed at us
Jets and the jet break.
Frail 2001.
TWO JETS OF HALF-ANGLE θ
f = 1 − cos θ · Etrue = f · Eiso · bursts per one we see = 1/f
Solid angle.
INSTRUMENT 4 · NARROW JETS
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Jet angle is user-chosen.
CH.07 / 09 — SWIFT IN OCTOBER 2026
Swift's last orbits
Swift's decay and LINK.
Swift resumes; reentry expected.
Status as of 11 October 2026.
CH.08 / 09 — LEGACY
From a secret archive to the edge of the universe
Each step needed a new instrument.
CH.09 / 09 — REFERENCES